Effects of type 2 diabetes on the viscoelastic behavior of human trabecular bone

Type 2 diabetes (T2D) is a well-known disease that impaired bone mechanical properties and increases the risk of fragility fracture. The bone tissue is a viscoelastic material that means the loading rate determines its mechanical properties. This study investigates the impact of T2D on the viscoelastic properties of human bone and its association with microstructure and biochemical properties.

Viscoelasticity is an important mechanical property of bone and for this the interaction of individual constituents of bone plays an important role. The viscoelastic nature of bone can be affected by aging and diseases, which can further influence its deformation and damage behavior.

The present study investigated the effects of T2D on the viscoelastic behavior of trabecular bone. The femoral heads of T2D (n = 26) and non-T2D (n = 40) individuals with hip fragility fractures were collected for this investigation. Following the micro-CT scanning of all bone samples, the stress relaxation and dynamic mechanical analysis (DMA) tests were performed to quantify the viscoelasticity of bone. Further, a correlation analysis was performed to investigate the effects of alteration in bone microstructural and biochemical parameters on viscoelasticity.

The stress relaxation and frequency sweep responses of T2D and non-T2D trabecular bone specimens were not found significantly different. However, the storage modulus, initial stiffness, and initial stress were found lower in T2D bone. The significant correlation of percentage stress relaxed is obtained between the mineral content (r= - 0.52, p-value = 0.003), organic content (r = 0.40, p-value = 0.02), and mineral-to-matrix ratio (r = - 0.43, p-value = 0.009). Further, storage and loss modulus were correlated with bone volume fraction (BV/TV) for both groups. The stress relaxation and frequency sweep characteristics were not found significantly connected with the other chemical, structural, or clinical parameters.

This study suggests that T2D does not affect the time-dependent response of human femoral trabecular bone. The viscoelastic properties are positively correlated with organic content and negatively correlated with mineral content.